1. Field of the Invention
This invention relates to a photographing apparatus for sequentially photographing and recording image information on a recording medium, such as a long microfilm.
2. Description of the Related Art
A typical conventional example of this kind of photographing apparatus is a rotary camera. A description will now be provided illustrating such a rotary camera.
The rotary camera is an automatic photographing apparatus, which sequentially receives materials to be preserved in the form of a microfilm, such as bills (drafts), checks, stock certificates, documents, drawings and the like, photographs the image information of the materials on a long film, and discharges the photographed materials outside the apparatus.
There have been known apparatuses including a plurality of photographing units, which simultaneously photograph a plurality of images on a plurality of films.
FIG. 25 illustrates an example of the above-described rotary camera, serving as the photographing apparatus. In FIG. 25, a photographing apparatus 101 includes a supply unit 102 for supplying a sheet-like object S' into the main body of the photographing apparatus, and discharging unit 103 for discharging the photographed object S' outside the main body of the apparatus. The apparatus 101 also includes an upstream-side conveying unit 104, an exposure unit 105 and a downstream-side conveying unit 106, which are sequentially disposed between the above-described supply unit 102 and discharging unit 103. An object S conveyed to the exposure unit 105 is imaged and exposed on a film F' (see FIG. 26) by an optical system 107 (to be described later).
An outer cover 110 covers the entire apparatus with its lower end portion contacting a circumferential portion of a base 108. The outer cover 110 is pivoted on a rear end portion of the base 108 by a hinge 109 so as to be openable to disclose the front side of the apparatus. A frame 111 mounted on the base 108 contains the upstream-side conveying unit 104 and the exposure unit 105 at its lower portion, the supply unit 102 at its front-end portion 111a, the downstream-side conveying unit 106 and the discharging unit 103 at its upper portion, and a driving system (not shown) at one end portion. A film chamber 112 for accommodating a film F is provided in front of the supply unit 102. An object detection sensor 113 is provided above the upstream-side conveying unit 104 at its upstream side in order to S detect the passage of the object S' and control, for example, a marking LED (light-emitting diode) array 123 and a shutter provided in the vicinity of a projection lens 122 shown in FIG. 26. The exposure unit 105 includes a pair of illuminating lamps 114 and 114', and a pair of parallel guide glasses 115 and 116 through which the object S' passes.
FIG. 26 illustrates the configuration of the optical system 107. That is, image light beams from the surface and the back of the object S passing through the guide glasses 115 and 116 constituting the exposure unit 105, which is positioned substantially at the center of the inside of the apparatus, are reflected by first mirrors 117 and 117', pass through slits 118 and 118' of a slit plate, respectively, and are imaged on to the film F' by an imaging lens 122 after being reflected by second, third and fourth mirrors 119, 120 and 121. The marking LED array 123 is fixed to a base structure (not shown) of the main body of the apparatus at a position adjacent to and outside the optical path of the surface-image light beam of the object S.
In one photographing method of a rotary camera, object images are photographed on the entire width of a long microfilm and the photographing operation is terminated at the end of the film (a simplex or duplex photographing operation). In another method, in which a reciprocating (duo) photographing operation is performed, object images are photographed on a half width of the microfilm. When the photographing operation on the half width has been completed, the microfilm is inverted in the direction of the width and object images are photographed on the other half width of the microfilm in the reverse direction. Apparatuses have been devised in which a film chamber (recording unit) for accommodating a microfilm is detachable as a camera unit. In such a photographing apparatus, a reciprocating (duo) photographing operation can be performed by making the camera unit in an upside-down state.
In the above-described conventional approach, the camera unit can be inserted in an upside-down state, and it is first detached from the main body of the apparatus when performing a reciprocating (duo) photographing operation by making the camera unit in an upside-down state. In such a case, however, since the camera unit can be inserted either in a normal state or in an upside-down state, the camera unit may be frequently inserted in a wrong posture. In addition, since there is no display of information relating to the exposed position on the microfilm, care must be taken when the camera unit is detached.
If the camera unit is inserted in a wrong posture, object images are not correctly photographed on the microfilm because exposed positions on the microfilm and the moving direction of the microfilm differ depending on the posture, so that photographed images may be unsuitable.
In a photographing apparatus using a long microfilm, in order to prevent a leading-edge portion or a trailing-edge portion of the film from being exposed to external light when loading the film or taking out and developing the film, feeding of the leading edge of the film (leader feeding) and feeding of the trailing edge of the film (trailer feeding) are performed. When loading the film, leader feeding is usually started after winding a certain amount of the leading-edge portion of the film around a takeup reel or the like. Film feeding in the photographing apparatus is performed, in many cases, at a very low speed because the reduction ratio of the apparatus is small, so that a long time is required for the film feeding.
In some photographing apparatuses using long microfilms, the amount fed from a leading-edge portion of the film is displayed on an odometer so that the used amount of the film or the current photographing position on the film is known. In other apparatuses, a warning (indicating a near-end state of the film) is provided when the exposed position approaches the end of the film.
In the above-described conventional approach, when performing a reciprocating photographing operation by inverting the film in the direction of the width, the film is completely wound after terminating the photographing operation, whereby photographed images are prevented from being exposed when taking out the film. In the above-described photographing apparatus, film feeding is performed at a very low speed because a photographing operation is performed at a high reduction ratio. In order to feed the film at a high speed when it is intended to perform only film feeding, for example, another motor for film feeding must be provided, or the gear ratio must be changed using a variable speed gear, thereby increasing the complexity of the configuration and the cost of the apparatus. Since film feeding is usually performed only at a low speed, a long time is required for feeding the film even if the fed amount of the film is small.
Since there is the possibility that a leading-edge portion of the film has been exposed, a photographing operation after inverting the film in the direction of the width must be terminated at a position more or less before the leading edge of the film, thereby causing wasteful use of the film.
Since the display of the odometer starts from a leading-edge portion of the film, the display does not indicate the exact amount of a photographable region. Similarly, a warning of a near-end state of the film is not provided based on the absolute amount of a photographable region.